366 PAUL S. RUSSELL 



members of two litters survived without evidence of disease while 

 the 6 members of the other two Utters promptly died of runt 

 disease as though the serum treatment had not been given. 

 Although showing sharp variation in eificacy between litters, it is 



16 18 20 22 24 26 28 30 32 34 36 38 40 

 DAYS OF LIFE 



Fig. 12. Mean weight-gain record of 3 separate litters 

 of C57BL/6 mice receiving 10 to 15 million DBA/i 

 spleen cells at birth. On the second, third and fourth 

 days of hfe each animal received intraperitoneal injec- 

 tions of 0-05 to 0-07 ml. of serum from C57BL/6 

 adults previously sensitized to DBA/i tissues. The upper 

 two curves represent litters treated with serum from 

 animals sensitized by injections of spleen cells in 

 adjuvant into the foot pads. For the lower curve the 

 animals were treated with serum from donors which had 

 rejected DBA/i skin grafts (see Methods section). The 

 bars represent a single standard deviation of the mean. 

 The "cell-adjuvant sensitized" serum appears to be 

 somewhat more effective in overcoming runt disease. 



clear from the data depicted in Fig. 13 that serum treatment can 

 retrieve animals at this stage from lethal runt disease which 

 rapidly overtakes controls in the same litter. Survivors of this 

 treatment reacted normally against DBA/i skin grafts in every 

 instance when they had reached a suitable size for grafting. 



